Just stumbled upon this marvelously loopy interview with the head of a Swiss Federal Ethics Committee. Said committee issued guidelines in 2008 pertaining to the dignity of plants. In Switzerland it is now permissible to harm plants, say for agriculture, but not to cause them arbitrary harm. An example of the latter: consider someone who casually decapitates some wildflowers on the road side.
The issue has come about because Swiss lawmakers and citizens were worried about the potential dangers of genetic technologies, and passed a law requiring that the dignity of creatures be considered in research. Unfortunately, they seem not to have adequately considered that plants are quite creaturely in their own way. Hence guidelines about how you might respect plant dignity, in research and more broadly. Nature went to the trouble of writing an editorial - as you might expect, plant biologists in Switzerland are flummoxed.